class X {
  function l(l: List<String>): List<String> = l
  function map(map: Map<String, Int>): Map<String, Int> = map
  function nullable(nullable: String?): String? = nullable
  function lambda(lambda: (String) -> Int): (String) -> Int = lambda
}

local x = new X {}

res1 = x.l(List("1", "2"))
res2 = x.map(Map("1", 1, "2", 2))
res3 = x.nullable("1")
res4 = x.nullable(null)
res5 = x.lambda((str) -> str.length).apply("hello")
